define get_subnet_locations() return $subnet_locations do
  @subnets = rs_cm.subnets.get()
  $list = []

  foreach @subnet in @subnets do
    $subnet = to_object(@subnet)
    $subnet_name = $subnet['details'][0]['name']
    $subnet_href = select($subnet['details'][0]['links'], {'rel':'self'})[0]['href']
    $subnet_network_href = select($subnet['details'][0]['links'], {'rel':'network'})[0]['href']

    # get the name of the subnet's network
    @network = first(rs_cm.get(href: $subnet_network_href))				# avoid?
    $network_name = @network.name

    # get the name of the subnet's cloud
    $cloud_href_split = split($subnet_href, '/')
    $subnet_cloud_href = '/' + $cloud_href_split[1] + '/' + $cloud_href_split[2] + '/' + $cloud_href_split[3]
    @cloud = first(rs_cm.get(href: $subnet_cloud_href))			# avoid?
    $cloud_name = @cloud.name

    # not all clouds use the concept of DCs or AZs
    sub on_error: skip do
   		$subnet_datacenter_href = select($subnet['details'][0]['links'], {'rel':'datacenter'})[0]['href']
      	@datacenter = first(rs_cm.get(href: $subnet_datacenter_href))			# avoid?
    	$datacenter_name = @datacenter.name
    end
    if ! $datacenter_name
      $datacenter_name = '-'
    end

    # append to the subnet locations array in known format
    $list_item = $cloud_name + ' :: ' + $datacenter_name + ' :: ' + $network_name + ' :: ' + $subnet_name
  	$list << $list_item
  end
  $subnet_locations = sort($list)
end